The document wishes the recipient a happy holidays and new year, hoping that 2014 brings prosperity and peace for all. It is from Applied Research & Photonics located in Harrisburg, Pennsylvania.
This document contains photos credited to various photographers and suggests creating a Haiku Deck presentation on SlideShare. It includes photos from derekbruff, tim caynes, mariacasa, and WordRidden with multiple photos from WordRidden. The document ends by encouraging the reader to get started making their own Haiku Deck presentation.
The document discusses various environmental issues including air pollution, water pollution, land pollution, climate change, deforestation, and desertification. It lists the group members working on the project and provides details on the causes and effects of different types of pollution. Major causes of deforestation mentioned are logging, mining, oil/gas extraction, cattle ranching, and agriculture. The causes of desertification include physical, biological, political, social, economic and cultural factors. Some ways to prevent environmental problems like global warming are reducing CFCs and waste burning, keeping the environment clean, planting trees, and using public transport.
Listado de credenciales estarán para su entrega a contar del lunes 6 de eneroEduardo Sanhueza
Este documento proporciona una lista de apellidos y nombres de personas. Contiene más de 500 entradas con el apellido paterno, materno y los nombres de cada persona de forma individualizada. La lista no incluye más información sobre las personas listadas.
Este documento contiene la lista de estudiantes matriculados en el curso de Álgebra lineal de la Facultad Eléctrica y Electrónica en el año 2015A. La lista incluye 33 nombres de estudiantes.
This document defines and discusses different types of subsidies. It begins by defining subsidies as unrecovered costs of public services financed through government budgets. Subsidies are classified as either narrow or broad, with narrow subsidies being direct monetary transfers and broad subsidies including non-monetary impacts. The document then outlines various types of subsidies such as production, consumption, export, employment and environmental subsidies. It provides examples and discusses the economic effects and rationale for subsidies, as well as issues like overuse and fiscal deficits. Specifics about India's large subsidy expenditures on fuel, food and other areas are also covered.
This document contains photos credited to various photographers and suggests creating a Haiku Deck presentation on SlideShare. It includes photos from derekbruff, tim caynes, mariacasa, and WordRidden with multiple photos from WordRidden. The document ends by encouraging the reader to get started making their own Haiku Deck presentation.
The document discusses various environmental issues including air pollution, water pollution, land pollution, climate change, deforestation, and desertification. It lists the group members working on the project and provides details on the causes and effects of different types of pollution. Major causes of deforestation mentioned are logging, mining, oil/gas extraction, cattle ranching, and agriculture. The causes of desertification include physical, biological, political, social, economic and cultural factors. Some ways to prevent environmental problems like global warming are reducing CFCs and waste burning, keeping the environment clean, planting trees, and using public transport.
Listado de credenciales estarán para su entrega a contar del lunes 6 de eneroEduardo Sanhueza
Este documento proporciona una lista de apellidos y nombres de personas. Contiene más de 500 entradas con el apellido paterno, materno y los nombres de cada persona de forma individualizada. La lista no incluye más información sobre las personas listadas.
Este documento contiene la lista de estudiantes matriculados en el curso de Álgebra lineal de la Facultad Eléctrica y Electrónica en el año 2015A. La lista incluye 33 nombres de estudiantes.
This document defines and discusses different types of subsidies. It begins by defining subsidies as unrecovered costs of public services financed through government budgets. Subsidies are classified as either narrow or broad, with narrow subsidies being direct monetary transfers and broad subsidies including non-monetary impacts. The document then outlines various types of subsidies such as production, consumption, export, employment and environmental subsidies. It provides examples and discusses the economic effects and rationale for subsidies, as well as issues like overuse and fiscal deficits. Specifics about India's large subsidy expenditures on fuel, food and other areas are also covered.
Terahertz (T-ray) techniques for measuring, profiling, and mapping of semiconductor features and doping concentration of via a T-ray volume imaging route, deep-level spectroscopy, and empirical modeling; and application thereof for semiconductor doping concentration thickness profiling and surface mapping for both undoped and doped semiconductors.
This paper outlines the basic technology and economic model of the core silicon technology. Silicon is the second most abundant element on the earth’s crust but there is no specific deposit or mine for silicon.
The only source for silicon is “sand” that the earth has an abundant supply. Here we outline the basic steps of manufacturing silicon ingot and wafers. It is projected that, once produced, these products will gain immediate market access, thus creating economic activities in a reasonably short period of time. The three initial products that could stem from the basic silicon ingot are silicon wafers, for both semiconductor and solar cell applications, and optical fiber for communication. This report focuses on the essential silicon
technology to produce silicon ingot, and silicon wafer, as the first step. Finally, the historic data available for the silicon wafer consumption per year have been modeled with the well-known Bass diffusion model.
It was found that with modified parameters, the Bass model fits the historic data well and the same model allows a projection for a few years in the future. This projected economic activities, therefore, encourages a social transformation towards a technological self-sufficiency.
Keywords: Silicon technology; Bass diffusion model; Silicon wafer consumption; Social transformation;
Technological self-sufficiency
DOI: 10.31031/NRS.2022.11.000760
Abstracts and Bios of the Chief Guest, Guest of Honor, distinguished Speakers and Panelists of the 2021 AABEA-FOBANA joint Seminar in Washington DC, November 27 and 28, 2021.
This document summarizes the results of a study that used terahertz imaging to quantify the lattice dilation of plasma-sprayed nickel films in four samples. The study found that the lattice spacing of the nickel films was greater than that of pure metallic nickel, indicating lattice dilation. The degree of dilation decreased in the order of the four samples and was correlated with their exposure to high energy electric fields. This provides direct evidence of lattice dilation in plasma-sprayed nickel due to experimental conditions.
The document reviews some of the highlights from the author's 2018, including two notable papers that were published. The first paper, published in the IEEE Transactions on Semiconductor Manufacturing, outlines a technique for nano-scale imaging and measurements without an electron microscope that overcomes the Abbe diffraction limit. A second paper published in the Journal of Nanoparticle Research addresses advances in nanoparticle imaging while suspended in a medium, and formally acknowledges the "Rahman-Tomalia effect". Both papers received positive feedback from colleagues in their respective fields.
Abstract— This paper demonstrates overcoming of the Abbe diffraction limit (ADL) on image resolution. Here, terahertz multispectral reconstructive imaging has been described and used for analyzing nanometer size metal lines fabricated on a silicon wafer. It has also been demonstrated that while overcoming the ADL is a required condition, it is not sufficient to achieve sub-nanometer image resolution with longer wavelengths. A nanoscanning technology has been developed that exploits the modified Beer-Lambert’s law for creating a measured reflectance data matrix and utilizes the ‘inverse distance to power equation’ algorithm for achieving 3D, sub-nanometer image resolution. The nano-lines images reported herein, were compared to SEM images. The terahertz images of 70 nm lines agreed well with the TEM images. The 14 nm lines by SEM were determined to be ~15 nm. Thus, the wavelength dependent Abbe diffraction limit on image resolution has been overcome. Layer-by-layer analysis has been demonstrated where 3D images are analyzed on any of the three orthogonal planes. Images of grains on the metal lines have also been analyzed. Unlike electron microscopes, where the samples must be in the vacuum chamber and must be thin enough for electron beam transparency, terahertz imaging is non-destructive, non-contact technique without laborious sample preparation.
Abstract:
This paper demonstrates overcoming of the Abbe diffraction limit (ADL) on image resolution. Here, terahertz multispectral reconstructive imaging has been described and used for analyzing nanometer size metal lines fabricated on a silicon wafer. It has also been demonstrated that while overcoming the ADL is a required condition, it is not sufficient to achieve sub-nanometer image resolution with longer wavelengths. A nanoscanning technology has been developed that exploits the modified Beer-Lambert’s law for creating a measured reflectance data matrix and utilizes the ‘inverse distance to power equation’ algorithm for achieving 3D, sub-nanometer image resolution. The nano-lines images reported herein, were compared to SEM images. The terahertz images of 70 nm lines agreed well with the TEM images. The 14 nm lines by SEM were determined to be 15 nm. Thus, the wavelength dependent Abbe diffraction limit on image resolution has been overcome. Layer-by-layer analysis has been demonstrated where 3D images are analyzed on any of the three orthogonal planes. Images of grains on the metal lines have also been analyzed. Unlike electron microscopes, where the samples must be in the vacuum chamber and must be thin enough for electron beam transparency, terahertz imaging is non-destructive, non-contact technique without laborious sample preparation.
Two critical nanoscale design parameters (CNDPs); namely, surface chemistry and interior compositions of poly(amidoamine) (PAMAM) dendrimers were systematically engineered to produce unique hyperpolarizable, electro-optical substrates. These electro-optically active dendritic films were demonstrated to produce high quality, continuous wave terahertz radiation when exposed to a suitable pump laser that could be used for spectrometry and molecular imaging. These dendrimer based dipole excitation (DDE) terahertz sources were used to construct a working spectrometer suitable for many practical applications including THz imaging and analysis of encapsulated hydrogen species in fullerenes.
Abstract
Terahertz spectral analysis has been conducted on epitaxially grown semiconductor structures. Epitaxially grown semiconductors are important for microelectronic and optoelectronic devices and also for integrated circuits
fabricated using semiconductors. In this paper, we report results of terahertz time-domain spectroscopy of grown
SiGe layers on Ge buffer and separately a Ge buffer that was grown on a Si <001> wafer. In particular, evolution of
the time-domain spectra as a function of thickness of both samples was investigated by the terahertz pump-probe
technique. Representative spectra were analyzed to determine the respective layers’ spectral signatures. It was found that the spectroscopic analysis uniquely identified different layers by characteristic absorbance peaks. In addition, terahertz imaging was conducted in a non-destructive, non-contact mode for detecting lattice stacking fault and dislocations. Sub-surface imaging of grown SiGe layers on Ge buffer and that of the Ge buffer grown on a Si wafer reveals interesting lattice features in both samples. A comparison with TEM images of the samples exhibits that the terahertz image reproduces the dimensions found from TEM images within the experimental error limits. In particular, 3D images of both samples were generated by the terahertz reconstructive technique. The images were analyzed by graphical means to determine the respective layer thicknesses. Thus, this technique offers a versatile tool for both semiconductor research and in-line inspections.
The document discusses observations of patterns in nature that suggest nature exhibits short-range order and long-range disorder. Samples of fabric and paper with particles distributed in grids were found to have irregular particle patterns that did not continue across whole layers. Google Earth images also showed tree distributions forming grids in sparse areas that disappeared in denser areas. Random forest and park images from around the world provided further examples, supporting the hypothesis that nature favors short-range order transitioning to long-range disorder over large scales.
Abstract
Terahertz sub-surface imaging offers an effective solution for surface and 3D imaging because of minimal
sample preparation requirements and its ability to “see” below the surface. Another important property is the ability
to inspect on a layer-by layer basis via a non-contact route, non-destructive route. Terahertz 3D imager designed
at Applied Research and Photonics (Harrisburg, PA) has been used to demonstrate reconstructive imaging with a
resolution of less than a nanometer. Gridding with inverse distance to power equations has been described for 3D
image formation. A continuous wave terahertz source derived from dendrimer dipole excitation has been used for
reflection mode scanning in the three orthogonal directions. Both 2D and 3D images are generated for the analysis
of silver iodide quantum dots’ size parameter. Layer by layer image analysis has been outlined. Graphical analysis
was used for particle size and layer thickness determinations. The demonstrated results of quantum dot particle
size checks well with those determined by TEM micrograph and powder X-ray diffraction analysis. The reported
non-contact measurement system is expected to be useful for characterizing 2D and 3D naomaterials as well as for process development and/or quality inspection at the production line.
This document describes a new mechanism for terahertz generation using dendrimer dipole excitation (DDE). Dendrimers are doped with chromophores to create multiple distributed dipole moments. When excited by a pump laser, these distributed dipoles radiate across a broadband terahertz frequency range. The document details the design of an electro-optic dendrimer material with a high electro-optic coefficient and second order susceptibility for efficient terahertz generation. It discusses the doping and poling process used to generate the distributed dipoles and align them. Measurement of the electro-optic coefficient and demonstration of terahertz generation from the material is also summarized.
This document summarizes a study that used terahertz spectroscopy to analyze the interaction between different dyes (natural dyes from pomegranate and blackberry, and an inorganic dye called Ruthenium) and titanium dioxide films. The study found that:
1) The terahertz spectra of the natural dye-sensitized films were similar to each other but distinct from the inorganic dye, with prominent absorption peaks around the same wavelengths.
2) The natural dyes permeated more uniformly through the titanium dioxide layers than the inorganic dye based on kinetic studies of dye penetration.
3) Surface profiling and 3D imaging of the films using terahertz radiation clearly showed defects and flaws on the titanium dioxide film.
Abstract: Non-destructive terahertz reflection interferometry offers many advantages for sub-surface inspection such as interrogation of hidden defects and measurement of layers’ thicknesses. Here, we describe a terahertz reflection interferometry (TRI) technique for non-contact measurement of paint panels where the paint is comprised of different layers of primer, basecoat, topcoat and clearcoat. Terahertz interferograms were generated by reflection from different layers of paints on a metallic substrate. These interferograms’ peak spacing arising from the delay-time response of respective layers, allow one to model the thicknesses of the constituent layers. Interferograms generated at different incident angles show that the interferograms are more pronounced at certain angles than others. This “optimum” angle is also a function of different paint and substrate combinations. An automated angular scanning algorithm helps visualizing the evolution of the interferograms as a function of incident angle and also enables the identification of optimum reflection angle for a given paint-substrate combination. Additionally, scanning at different points on a substrate reveals that there are observable variations from one point to another of the same sample over its entire surface area. This ability may be used as a quality control tool for in-situ inspection in a production line.
Electro-optic Dendrimer is used to generate milliwatts of terahertz power by difference frequency
method. A terahertz time-domain spectrometer (THz-TDS) has been designed around this source that
exhibits wide broadband terahertz range, 0.1 to 35 THz. Examples of molecular characterization are discussed
for three common explosives and the vibrational states of Fullerenes. The explosives’ spectra are
unique for each explosive that allow detection and identification of the species. The Fullerenes C60 and
H2@C60 also exhibit distinctively different spectra and absorbance states indicating that the THz-TDS is
suitable for probing increased number of vibrational states expected from molecular vibrations.
2011 Elsevier B.V. All rights reserved.
http://thz-pacifichem.blogspot.com/
Call for Abstracts
Advances in Terahertz Spectroscopy and Imaging (#413)
THE INTERNATIONAL CHEMICAL CONGRESS OF
PACIFIC BASIN SOCIETIES
Honolulu, Hawaii, USA DECEMBER 15 - 20, 2015
Dear Colleague:
It is our great pleasure to announce a symposium on “Advances in Terahertz Spectroscopy and Imaging” at the Pacifichem 2015 in Hawaii. Please see the link above for details. Contributions are solicited addressing subjects from all walks of terahertz applications. As an emerging area of science and technology, terahertz applications, such as spectroscopy, reflectometry and imaging, have the potential for addressing some of the critical problems of the 21st century. As indicated by increased attendance and number of papers in the past, the proposed symposium will fill a gap in the technical program by attracting the terahertz spectroscopy and related communities from all over the world. While there are other spectroscopic techniques, terahertz technology provides unique information that is not available from the predecessors. Therefore, this symposium solicits papers on the advances of terahertz applications in crucial matters such as: biomedical research, early detection of skin cancer, transdermal drug delivery, biopharmaceuticals, materials for energy, conservation and forensic science, security & screening, geology and minerals, semiconductors and any other relevant areas. This symposium will present an opportunity for the exchange of knowledge in a global forum, including results and discussions of current and breakthrough terahertz techniques and their applications. Papers, including spectroscopic, reflectometry and imaging techniques on the above mentioned areas and other terahertz applications in solving important problems are welcome. Formal abstracts submission will be open from January 1 – April 3, 2015. See this link for details of submission: http://www.pacifichem.org/congress-details/abstracts/
Sincerely yours,
Anis Rahman (USA): a.rahman@arphotonics.net
Choonho Kim (S Korea): chkim1202@gmail.com
Wolfgang Jaeger (Canada): wolfgang.jaeger@ualberta.ca
Sing Kiong Nguang (New Zealand): sk.nguang@auckland.ac.nz
Yacov Shamash (USA): yacovshamash@yahoo.com
This document describes a terahertz non-invasive sub-surface nano-scanner and 3D imager. It uses terahertz radiation, which can penetrate non-metallic materials, to perform non-destructive subsurface scanning and 3D imaging. Examples are given of using it to detect coating penetration into paint and reveal periodic patterns in semiconductor wafers without defects. The system performs 3D scans to profile sample layers and reconstruct 3D images. It has potential applications in semiconductor inspection, medical imaging of skin and tissue, and other non-destructive testing of non-metallic layered composites.
Terahertz (T-ray) techniques for measuring, profiling, and mapping of semiconductor features and doping concentration of via a T-ray volume imaging route, deep-level spectroscopy, and empirical modeling; and application thereof for semiconductor doping concentration thickness profiling and surface mapping for both undoped and doped semiconductors.
This paper outlines the basic technology and economic model of the core silicon technology. Silicon is the second most abundant element on the earth’s crust but there is no specific deposit or mine for silicon.
The only source for silicon is “sand” that the earth has an abundant supply. Here we outline the basic steps of manufacturing silicon ingot and wafers. It is projected that, once produced, these products will gain immediate market access, thus creating economic activities in a reasonably short period of time. The three initial products that could stem from the basic silicon ingot are silicon wafers, for both semiconductor and solar cell applications, and optical fiber for communication. This report focuses on the essential silicon
technology to produce silicon ingot, and silicon wafer, as the first step. Finally, the historic data available for the silicon wafer consumption per year have been modeled with the well-known Bass diffusion model.
It was found that with modified parameters, the Bass model fits the historic data well and the same model allows a projection for a few years in the future. This projected economic activities, therefore, encourages a social transformation towards a technological self-sufficiency.
Keywords: Silicon technology; Bass diffusion model; Silicon wafer consumption; Social transformation;
Technological self-sufficiency
DOI: 10.31031/NRS.2022.11.000760
Abstracts and Bios of the Chief Guest, Guest of Honor, distinguished Speakers and Panelists of the 2021 AABEA-FOBANA joint Seminar in Washington DC, November 27 and 28, 2021.
This document summarizes the results of a study that used terahertz imaging to quantify the lattice dilation of plasma-sprayed nickel films in four samples. The study found that the lattice spacing of the nickel films was greater than that of pure metallic nickel, indicating lattice dilation. The degree of dilation decreased in the order of the four samples and was correlated with their exposure to high energy electric fields. This provides direct evidence of lattice dilation in plasma-sprayed nickel due to experimental conditions.
The document reviews some of the highlights from the author's 2018, including two notable papers that were published. The first paper, published in the IEEE Transactions on Semiconductor Manufacturing, outlines a technique for nano-scale imaging and measurements without an electron microscope that overcomes the Abbe diffraction limit. A second paper published in the Journal of Nanoparticle Research addresses advances in nanoparticle imaging while suspended in a medium, and formally acknowledges the "Rahman-Tomalia effect". Both papers received positive feedback from colleagues in their respective fields.
Abstract— This paper demonstrates overcoming of the Abbe diffraction limit (ADL) on image resolution. Here, terahertz multispectral reconstructive imaging has been described and used for analyzing nanometer size metal lines fabricated on a silicon wafer. It has also been demonstrated that while overcoming the ADL is a required condition, it is not sufficient to achieve sub-nanometer image resolution with longer wavelengths. A nanoscanning technology has been developed that exploits the modified Beer-Lambert’s law for creating a measured reflectance data matrix and utilizes the ‘inverse distance to power equation’ algorithm for achieving 3D, sub-nanometer image resolution. The nano-lines images reported herein, were compared to SEM images. The terahertz images of 70 nm lines agreed well with the TEM images. The 14 nm lines by SEM were determined to be ~15 nm. Thus, the wavelength dependent Abbe diffraction limit on image resolution has been overcome. Layer-by-layer analysis has been demonstrated where 3D images are analyzed on any of the three orthogonal planes. Images of grains on the metal lines have also been analyzed. Unlike electron microscopes, where the samples must be in the vacuum chamber and must be thin enough for electron beam transparency, terahertz imaging is non-destructive, non-contact technique without laborious sample preparation.
Abstract:
This paper demonstrates overcoming of the Abbe diffraction limit (ADL) on image resolution. Here, terahertz multispectral reconstructive imaging has been described and used for analyzing nanometer size metal lines fabricated on a silicon wafer. It has also been demonstrated that while overcoming the ADL is a required condition, it is not sufficient to achieve sub-nanometer image resolution with longer wavelengths. A nanoscanning technology has been developed that exploits the modified Beer-Lambert’s law for creating a measured reflectance data matrix and utilizes the ‘inverse distance to power equation’ algorithm for achieving 3D, sub-nanometer image resolution. The nano-lines images reported herein, were compared to SEM images. The terahertz images of 70 nm lines agreed well with the TEM images. The 14 nm lines by SEM were determined to be 15 nm. Thus, the wavelength dependent Abbe diffraction limit on image resolution has been overcome. Layer-by-layer analysis has been demonstrated where 3D images are analyzed on any of the three orthogonal planes. Images of grains on the metal lines have also been analyzed. Unlike electron microscopes, where the samples must be in the vacuum chamber and must be thin enough for electron beam transparency, terahertz imaging is non-destructive, non-contact technique without laborious sample preparation.
Two critical nanoscale design parameters (CNDPs); namely, surface chemistry and interior compositions of poly(amidoamine) (PAMAM) dendrimers were systematically engineered to produce unique hyperpolarizable, electro-optical substrates. These electro-optically active dendritic films were demonstrated to produce high quality, continuous wave terahertz radiation when exposed to a suitable pump laser that could be used for spectrometry and molecular imaging. These dendrimer based dipole excitation (DDE) terahertz sources were used to construct a working spectrometer suitable for many practical applications including THz imaging and analysis of encapsulated hydrogen species in fullerenes.
Abstract
Terahertz spectral analysis has been conducted on epitaxially grown semiconductor structures. Epitaxially grown semiconductors are important for microelectronic and optoelectronic devices and also for integrated circuits
fabricated using semiconductors. In this paper, we report results of terahertz time-domain spectroscopy of grown
SiGe layers on Ge buffer and separately a Ge buffer that was grown on a Si <001> wafer. In particular, evolution of
the time-domain spectra as a function of thickness of both samples was investigated by the terahertz pump-probe
technique. Representative spectra were analyzed to determine the respective layers’ spectral signatures. It was found that the spectroscopic analysis uniquely identified different layers by characteristic absorbance peaks. In addition, terahertz imaging was conducted in a non-destructive, non-contact mode for detecting lattice stacking fault and dislocations. Sub-surface imaging of grown SiGe layers on Ge buffer and that of the Ge buffer grown on a Si wafer reveals interesting lattice features in both samples. A comparison with TEM images of the samples exhibits that the terahertz image reproduces the dimensions found from TEM images within the experimental error limits. In particular, 3D images of both samples were generated by the terahertz reconstructive technique. The images were analyzed by graphical means to determine the respective layer thicknesses. Thus, this technique offers a versatile tool for both semiconductor research and in-line inspections.
The document discusses observations of patterns in nature that suggest nature exhibits short-range order and long-range disorder. Samples of fabric and paper with particles distributed in grids were found to have irregular particle patterns that did not continue across whole layers. Google Earth images also showed tree distributions forming grids in sparse areas that disappeared in denser areas. Random forest and park images from around the world provided further examples, supporting the hypothesis that nature favors short-range order transitioning to long-range disorder over large scales.
Abstract
Terahertz sub-surface imaging offers an effective solution for surface and 3D imaging because of minimal
sample preparation requirements and its ability to “see” below the surface. Another important property is the ability
to inspect on a layer-by layer basis via a non-contact route, non-destructive route. Terahertz 3D imager designed
at Applied Research and Photonics (Harrisburg, PA) has been used to demonstrate reconstructive imaging with a
resolution of less than a nanometer. Gridding with inverse distance to power equations has been described for 3D
image formation. A continuous wave terahertz source derived from dendrimer dipole excitation has been used for
reflection mode scanning in the three orthogonal directions. Both 2D and 3D images are generated for the analysis
of silver iodide quantum dots’ size parameter. Layer by layer image analysis has been outlined. Graphical analysis
was used for particle size and layer thickness determinations. The demonstrated results of quantum dot particle
size checks well with those determined by TEM micrograph and powder X-ray diffraction analysis. The reported
non-contact measurement system is expected to be useful for characterizing 2D and 3D naomaterials as well as for process development and/or quality inspection at the production line.
This document describes a new mechanism for terahertz generation using dendrimer dipole excitation (DDE). Dendrimers are doped with chromophores to create multiple distributed dipole moments. When excited by a pump laser, these distributed dipoles radiate across a broadband terahertz frequency range. The document details the design of an electro-optic dendrimer material with a high electro-optic coefficient and second order susceptibility for efficient terahertz generation. It discusses the doping and poling process used to generate the distributed dipoles and align them. Measurement of the electro-optic coefficient and demonstration of terahertz generation from the material is also summarized.
This document summarizes a study that used terahertz spectroscopy to analyze the interaction between different dyes (natural dyes from pomegranate and blackberry, and an inorganic dye called Ruthenium) and titanium dioxide films. The study found that:
1) The terahertz spectra of the natural dye-sensitized films were similar to each other but distinct from the inorganic dye, with prominent absorption peaks around the same wavelengths.
2) The natural dyes permeated more uniformly through the titanium dioxide layers than the inorganic dye based on kinetic studies of dye penetration.
3) Surface profiling and 3D imaging of the films using terahertz radiation clearly showed defects and flaws on the titanium dioxide film.
Abstract: Non-destructive terahertz reflection interferometry offers many advantages for sub-surface inspection such as interrogation of hidden defects and measurement of layers’ thicknesses. Here, we describe a terahertz reflection interferometry (TRI) technique for non-contact measurement of paint panels where the paint is comprised of different layers of primer, basecoat, topcoat and clearcoat. Terahertz interferograms were generated by reflection from different layers of paints on a metallic substrate. These interferograms’ peak spacing arising from the delay-time response of respective layers, allow one to model the thicknesses of the constituent layers. Interferograms generated at different incident angles show that the interferograms are more pronounced at certain angles than others. This “optimum” angle is also a function of different paint and substrate combinations. An automated angular scanning algorithm helps visualizing the evolution of the interferograms as a function of incident angle and also enables the identification of optimum reflection angle for a given paint-substrate combination. Additionally, scanning at different points on a substrate reveals that there are observable variations from one point to another of the same sample over its entire surface area. This ability may be used as a quality control tool for in-situ inspection in a production line.
Electro-optic Dendrimer is used to generate milliwatts of terahertz power by difference frequency
method. A terahertz time-domain spectrometer (THz-TDS) has been designed around this source that
exhibits wide broadband terahertz range, 0.1 to 35 THz. Examples of molecular characterization are discussed
for three common explosives and the vibrational states of Fullerenes. The explosives’ spectra are
unique for each explosive that allow detection and identification of the species. The Fullerenes C60 and
H2@C60 also exhibit distinctively different spectra and absorbance states indicating that the THz-TDS is
suitable for probing increased number of vibrational states expected from molecular vibrations.
2011 Elsevier B.V. All rights reserved.
http://thz-pacifichem.blogspot.com/
Call for Abstracts
Advances in Terahertz Spectroscopy and Imaging (#413)
THE INTERNATIONAL CHEMICAL CONGRESS OF
PACIFIC BASIN SOCIETIES
Honolulu, Hawaii, USA DECEMBER 15 - 20, 2015
Dear Colleague:
It is our great pleasure to announce a symposium on “Advances in Terahertz Spectroscopy and Imaging” at the Pacifichem 2015 in Hawaii. Please see the link above for details. Contributions are solicited addressing subjects from all walks of terahertz applications. As an emerging area of science and technology, terahertz applications, such as spectroscopy, reflectometry and imaging, have the potential for addressing some of the critical problems of the 21st century. As indicated by increased attendance and number of papers in the past, the proposed symposium will fill a gap in the technical program by attracting the terahertz spectroscopy and related communities from all over the world. While there are other spectroscopic techniques, terahertz technology provides unique information that is not available from the predecessors. Therefore, this symposium solicits papers on the advances of terahertz applications in crucial matters such as: biomedical research, early detection of skin cancer, transdermal drug delivery, biopharmaceuticals, materials for energy, conservation and forensic science, security & screening, geology and minerals, semiconductors and any other relevant areas. This symposium will present an opportunity for the exchange of knowledge in a global forum, including results and discussions of current and breakthrough terahertz techniques and their applications. Papers, including spectroscopic, reflectometry and imaging techniques on the above mentioned areas and other terahertz applications in solving important problems are welcome. Formal abstracts submission will be open from January 1 – April 3, 2015. See this link for details of submission: http://www.pacifichem.org/congress-details/abstracts/
Sincerely yours,
Anis Rahman (USA): a.rahman@arphotonics.net
Choonho Kim (S Korea): chkim1202@gmail.com
Wolfgang Jaeger (Canada): wolfgang.jaeger@ualberta.ca
Sing Kiong Nguang (New Zealand): sk.nguang@auckland.ac.nz
Yacov Shamash (USA): yacovshamash@yahoo.com
This document describes a terahertz non-invasive sub-surface nano-scanner and 3D imager. It uses terahertz radiation, which can penetrate non-metallic materials, to perform non-destructive subsurface scanning and 3D imaging. Examples are given of using it to detect coating penetration into paint and reveal periodic patterns in semiconductor wafers without defects. The system performs 3D scans to profile sample layers and reconstruct 3D images. It has potential applications in semiconductor inspection, medical imaging of skin and tissue, and other non-destructive testing of non-metallic layered composites.
More from Applied Research and Photonics, Inc. (20)
1. Happy Holidays &
Happy New Year!
May 2014 bring
prosperity and
peace for All!
Applied Research & Photonics
470 Friendship Road, Suite 10, Harrisburg, PA 17111
http://arphotonics.net